The invention relates to a fuel injection nozzle for insertion in internal combustion engines and includes a valve needle having a throttle pin arranged downstream of a sealing cone as well as a subsequent integral sprayforming pin of a smaller diameter. Valve needles of this type are opened in opposition to the flow direction of the fuel and against a closing force. A nozzle body which receives the valve needle has a central cylindrical injection port arrranged to receive the pin and further includes a conical area that preferably serves as a valve seat. Also, in nozzles of this design, the conical area communicates with the injection port and the throttle pin, during a full needle stroke, is adapted to merge from the cylindrical injection port, whereas the spray-forming pin is still extended into the port.
In conventional fuel injection nozzles of this type, the narrowest flow cross section with a fully opened valve differs in the individual nozzles. However, since, on the other hand, the injection pressure effected by the injection pump is constant, this leads to quantity fluctuations of the fuel to be injected at the individual nozzles. The quality of adjustment of the fuel injection pump as well as of the nozzles is naturally dependent on the extent of quantity fluctuation of the individual nozzles installed in an engine.